1. Technical Field of the Invention
The present invention relates to a subscriber feature within a telecommunications system and, in particular, to a subscriber feature for providing different terminating call treatments for incoming calls toward a particular subscriber terminal.
2. Description of Related Art
As stored program controlled (SPC) switching systems have evolved, a wide variety of useful subscriber features have been developed to extend the communication capabilities such systems provide. One example is call forwarding where a subscriber provides a "forward to" directory number to the switching system and the switching system thereafter forwards all incoming calls for the subscriber to the designated "forward to" number. Other examples of subscriber features include call waiting, voice mail, call conferencing, call transfer, and automatic callback. Due to low subscription costs and added subscriber capabilities provided by these subscriber features, normal telecommunications subscribers usually have more than one subscription to such subscriber features.
However, even with the advancement of such SPC switching systems and subscriber features, many telecommunications subscribers find the interaction of the above subscriber features confusing and limiting. For example, if a subscriber is already in speech connection, all subsequent incoming calls will be provided with the same terminating call treatment by a particular one of the subscriber features enumerated above. As an illustration, if two or more incoming calls are received by a busy subscriber who has both call waiting (CAW) and call forwarding on busy (CFB) features activated, there is currently no mechanism to selectively provide a different terminating call treatment to the received incoming calls. The subscriber service features are not able to selectively forward one particular incoming call to a "forward-to-number", yet allow another incoming call to call wait on the existing connection based upon a discriminating review of the calling party numbers associated with the two incoming calls.
A number of implementations have been proposed to alleviate some of the limitations of the existing systems as illustrated by the above problem. One implementation enables a telecommunications subscriber to selectively assign a group of directory numbers to each subscriber feature. For example, a first group of directory numbers are assigned to the call waiting feature and a second group of directory numbers are assigned to the call forwarding feature. If an incoming call is received from a caller having a directory number contained within the first group, the call waiting service is provided. Similarly, if an incoming call is received from a caller having a directory number contained within the second group, the call forwarding service is instead provided for that particular incoming call. Although the above implementation enables a telecommunications subscriber to selectively associate a particular subscriber feature with a specific calling party number, it still has certain undesirable characteristics.
For the above implementation, the subscriber must have previously inputted all relevant directory numbers into the switching system and have manually associated those numbers with a particular subscriber feature. Accordingly, if an incoming call is received from a directory number not identified by any one of the previously stored directory numbers, the switching system has no means to determine which one of the available subscriber features to apply. The same is true if no number is delivered by the network. Furthermore, if the subscriber wishes to rearrange or modify a directory number assigned to a particular subscriber feature, such modifications must be made manually by the subscriber to the switching system before the desired operation is provided.
Accordingly, there is a need for a mechanism to enable a telecommunications exchange to more flexibly provide terminating call treatments to incoming calls.